1. Field of the Invention
This invention relates to electronic devices and, more particularly, to cooling systems for electronic devices.
2. Description of the Related Art
The following descriptions and examples are not admitted to be prior art by virtue of their inclusion within this section.
Exposure to excessive heat can shorten the life of or lead to the failure of electronic components. As a result, most electronic devices include active cooling systems to thermally manage their internal temperatures. These cooling systems employ methods of heat removal such as forced air flow or thermoelectric cooling to cool the components of the computer that are most likely to experience excessive heat. The most common form of active cooling in computers involves the use of a fan to force the flow of lower temperature ambient air through the device to cool the components that generate the most heat. Generally, processors and power supplies are most threatened by exposure to excessive heat. Cooling systems have evolved to become more sophisticated, and most now use temperature sensors to logically adjust fan speed. Newer cooling systems implement temperature control schemes that typically focus on either maximizing the cooling capacity of the system by increasing fan speed and air flow and by reducing the amount of heat generated by limiting the performance of the computer.
A negative attribute of many active cooling systems that use one or more fans to cool a computer is that the fan(s) can produce a large amount of noise which may become bothersome to the user. Cooling systems may achieve quieter cooling by opening air passages and rerouting airflow, increasing fan speed, limiting the amount of heat that the computer generates, or some combination thereof. With respect to particularly compact electronic devices, such portable personal computers (PCs), having components that are packaged very close together, it may be difficult to modify air flow through any means other than increasing fan speed. Limiting the amount of heat generated by an electronic device may be possible, but this solution is usually accompanied by the unwanted side effect of limiting the performance and processing power of the device. Since cooling systems that emit too much noise can be bothersome to a user, existing cooling systems are generally designed to operate below a selected noise level. The selected noise level may be determined by empirical or ergonomic testing to determine a target noise level at which the device will operate based on the acceptable sound level for an exemplary operating environment. For instance, a desktop computer may be assumed to operate in a relatively quiet office environment, so its cooling system may be configured to operate below a selected noise level that is considered to be acceptable for an office environment. The amount of noise emitted by the desktop computer may be limited by modifying cooling system parameters such as fan speed and air flow. In other words, the computer may be designed so that its cooling system will not emit more noise than the selected noise level that corresponds to the anticipated operating environment.